There were two other larger HTR plants. One in the USA and one in Germany but both are now shut down. China actually has serious plans to follow up with a lot more plants. Perhaps a thousand of these reactors or more Until 2020-2025, these small mass produced reactors will be secondary to a massive build of larger nuclear reactors (China is order 100 Westinghouse AP1000 reactors, 1.25 GW- 1.7GW by 2020)
Schematic of the HTR-PM (High temperature reactor pebble bed module) Link is to eight page design paper.
A 200 MWe high temperature reactor will be the safest nuclear power plant ever designed and built. High temperature reactors can be adapted to use thorium for fuel and the plan is for factory mass produced reactors. Two year construction times and mass production driving costs down to less than half the cost of the first units. China sees these as supplemental reactors to the big reactors. They will be used in smaller cities and towns and by factories for generating industrial heat. Also, they are looking to use heat for hydrogen generation, desalination and coal liquification (at least that would be cleaner than straight coal burning).
The major safety issue regarding nuclear reactors lies in how to cool them efficiently, as they continue to produce residual heat even after shutdown. Gas-cooled reactors discharge surplus heat and don’t need additional safety systems like water-cooled reactors do. The HTR-10 was subject to a test of its intrinsic safety in September 2004 when, as an experiment, it was shut down with no cooling. Fuel temperature reached less than 1600 C and there was no failure.
“Using the existing operating HTR-10 reactor at the Institute of Nuclear and New Energy Technology of Tsinghua University in Beijing, we have already done what would be unthinkable in a conventional reactor—we switched off the helium coolant and successfully let the reactor cool down by itself,” said Wu.
A Simpler, More Rational Way to Think about Nuclear Safety: FOUR LEVELS OF SAFETY*
[Definition developed by Professor Lawrence Lidsky, Massachusetts Institute of Technology.]
No hazardous materials or confined energy sources.
No need for active systems in event of subsystem failure. Immune to major structural failure and operator error.
No need for active systems in event of subsystem failure. No immunity to major structural failure or operator error.
Positive response required to subsystem malfunction or operator error. Defense in depth. No immunity to major structural failure.
The MHR is the only reactor that meets the criterion of Level 1 safety.
Second, the modular design enables the plant to be assembled much quicker and cost-effectively than traditional nuclear generators. Its streamlined construction timetable is also a first for the nuclear power industry, where designing and building generators usually take decades, rather than years.
The modules are manufactured from standardized components that can be mass-produced, shipped by road or rail and assembled relatively quickly. The new plants are smaller and new modules can be added as needed. Multiple reactors can be linked around one or more turbines, all monitored from a single control room. The site of the Shidaowan project will install 18 additional modules, which will total 3,800 MWe.
A demonstration high-temperature gas-cooled reactor, the HTR-PM of 200 MWe was approved in November 2005, to be built at Shidaowan, near Rongcheng in Weihai city, Shandong province by Huaneng Shidaowan Nuclear Power Company. This consortium is led by the China Huaneng Group Co. - the country's largest generating utility but hitherto without nuclear capacity. The project received environmental clearance in March 2008 for construction start in 2009 and commissioning by 2013.
The Modular High Temperature Pebble Bed reactor should also use half of the steel and one third of the concrete of Light Water reactors.
A 10 MWt high-temperature gas-cooled demonstration reactor (HTR-10), having fuel particles compacted with graphite moderator into 60mm diameter spherical balls (pebble bed) was commissioned in 2000 by the Institute of Nuclear Energy Technology (INET) at Tsinghua University near Beijing. It reached full power in 2003 and has an outlet temperature of 700-950°C and may be used as a source of process heat for heavy oil recovery or coal gasification. It is similar to the South African PBMR intended for electricity generation. It was subject to a test of its intrinsic safety in September 2004 when as an experiment it was shut down with no cooling. Fuel temperature reached less than 1600°C and there was no failure.
Initially the HTR-10 has been coupled to a steam turbine power generation unit, but second phase plans are for it to operate at 950°C and drive a gas turbine, as well as enabling R&D in heat application technologies. This phase will involve an international partnership with Korea Atomic Energy Research Institute (KAERI), focused particularly on hydrogen production.
A key R&D project is the demonstration Shidaowan HTR-PM of 200 MWe (two reactor modules, each of 250 MWt) which is being built at Shidaowan in Shandong province, driving a single steam turbine at about 40% thermal efficiency.
The 40% efficiency of a MHR driving steam can turbine can be seen. China will switch to higher efficiency gas turbine cycle in later versions.
The size was reduced to 250 MWt from earlier 458 MWt modules in order to retain the same core configuration as the prototype HTR-10 and avoid moving to an annular design like South Africa's PBMR.
China Huaneng Group, one of China's major generators, is the lead organization in the consortium with China Nuclear Engineering & Construction Group (CNEC) and Tsinghua University's INET, which is the R&D leader. Chinergy (a 50-50 joint venture of INET and CNEC) is the main contractor for the nuclear island. Projected cost is US$ 430 million, with the aim for later units being US$ 1500/kWe. The licensing process is under way with NNSA and construction is likely to start early in 2009 with completion expected in 2013.
The HTR-PM will pave the way for 18 (3x6) further 200 MWe units at the same site in Weihai city - total 3800 MWe - also with steam cycle. INET is in charge of R&D, and is aiming to increase the size of the 250 MWt module and also utilise thorium in the fuel. Eventually a series of HTRs, possibly with Brayton cycle directly driving the gas turbines, will be factory-built and widely installed throughout China.
In March 2005 an agreement between PBMR of South Africa and Chinergy of Beijing was announced. PBMR Pty Ltd is has been taking forward the HTR concept (based on earlier German work) since 1993 and is ready to build a 125 MWe demonstration plant. Chinergy Co. is drawing on the small operating HTR-10 research reactor at Tsinghua University which is the basis of their 100 MWe HTR-PM demonstration module which also derives from the earlier German development.
Both PBMR and HTR-PM are planned for operation about 2013. The new agreement is for cooperation on the demonstration projects and subsequent commercialisation, since both parties believe that the inherently safe pebble bed technology built in relatively small units will eventually displace the more complex light water reactors.
General Atomics of the United States with Russian partners have had an advanced modular helium reactor design completed since 2001, but actual construction has been stalled
China will be heading towards the GT-MHR design in stages of actually completed reactors.
The gas turbine part of the reactor design
The chinese steam cycle MHR will achieve much of the benefits of the Gas Turbine MHR and the gas turbine version chinese reactors will have roughly the same benefits in terms of less nuclear waste.
High temperature reactor history
Iris reactor license application inactive until 2010.
Documentation on the Iris reactor
High Temperature reactor conference
France also has a high temperature reactor design the Anteres, but they do not have firm construction plans
Cleantechnica followed the coverage provided here and adds some interesting information